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Heaton 1975: 173 states that the discrimination index of an item indicates the extent to which the item discriminates between the testees separating
the more from the less able. The index of discrimination tell us whether those students who performed well on the whole test tended to do or badly on each item
in the test. The writer calculated the item discrimination using the formula:
1
2 2
2 1
− Σ
+ Σ
− =
ni ni
x x
ML MH
t
where: MH : the mean of upper group
ML : the mean of lower group
2 1
x Σ : the sum of deviation of each students in upper group
2 2
x Σ : the sum of deviation of each students in lower group
The computation of the discriminating power can be seen in appendix 4.
3.7 Scoring System
Testing speaking requires the subjective judgments on the part of the raters, thus, teacher’ perception of oral assessment and oral assessment rating
scales affect the testing process substantially Weir, 1990. To minimize subjective judgments, the writer and the teacher score the students used rating
scales developed by David P. Harris modified by Walter Bartz and then the score divided by two.
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In this study, the writer gave oral test to the students and analyzed their scores to measure the improvement and gave scores on pronunciation, grammar,
vocabulary, fluency and comprehension. In order for the raw scores to become more meaningful numerical data,
they should be converted to numerical data, which had been processed to the scale of 0 to 100, so the scores of the students was multiply by 4. Then, the processed
scores could be used as a basic to make decisions. If all students, scores were arranged from the highest to the lowest, it would be easier to know the position of
a student in hisher group. The measurement of the students achievement that is suggested by Harris
1969: 134 could be interpreted with the following table.
Table 4 Students achievement
Criteria of mastery Grade
91-100 Excellent 81-90 Very
Good 71-80 Good
61-70 Fair 51-60 Poor
Less than 50 Very Poor
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3.8 Method of Data Analysis
After collecting the data, the writer analyzed them by using statistical analysis. The writer transcribed the students’ oral test on paper and then she
scored the result of oral test. To differentiate whether the students’ result of speaking English using
comic and without using comic is significant or not the writer used the t-test formula as follow:
⎟ ⎠
⎞ ⎜
⎝ ⎛
+ ⎟
⎠ ⎞
⎜ ⎝
⎛ −
+ +
− =
Nc Ne
Nc Ne
Ssc Sse
Mc Me
t 1
1 2
Where t : t-test
Me : the mean difference of the experiment group Mc : the mean difference of control group
Sse : sum of quadrate deviation of the experiment group Ssc : sum of quadrate deviation of the control group
Ne : the number of experiment group Nc : the number of control group
Before calculating the t-test the writer calculated mean, variance, and standard deviation.
3.8.1 Mean
Mean is computed by using the formula:
N X
X Σ
= where:
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X : mean X
Σ : sum of scores N : number of scores
3.8.2 Variance
The variance of a group of scores is computed by using the following formula:
1
2 2
2
− ΣΧ
− ΣΧ
= N
N S
where:
2
S : variance X : individual scores
N : number of scores in the group
3.8.3 Standard Deviation
The standard deviation of a group of scores is computed by using the following formula:
1
2 2
− ΣΧ
− ΣΧ
= N
N S
where: S : standard deviation
X : individual scores N : number of scores in group
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CHAPTER IV DATA ANALYSIS AND THE RESULT OF THE STUDY
This chapter deals with discussion of the experiment, computation between the two means, test of significance, grades of achievement, questionnaire
analysis and discussion of the research findings.
4.1 Test
4.1.1 The Pretest
The pretest was conducted on 30
th
April 2007. Both of groups were given the same comic and they were asked to do the test individually in retelling the
story of comic in 3-5 minutes. The result of the pretest can be seen in appendix 7.
4.1.2 The Experimental Treatment
After conducted the pretest, the writer conducted the experimental treatment. The writer taught three times a week for experiment group by using
comic as an alternative way of teaching speaking. On the other hand, the control group was taught by their own English teacher without using comic.
The procedure of the treatment between experiment group and control group.
Table 5 The Experimental Treatment
Experiment Group Control Group
1 First meeting
1 The writer handed out the comic
entitled The Knight Rider to the students.
1. First meeting
1 The teacher handed out the written
text entitled The Princess and the Pea to the students.
